Working speed control, function

W07.16-1059-79

General

As soon as a power take-off is switched on, the electronic working speed control is activated. To do this up to three power take-offs can be parameterized differently according to the vehicle equipment. The parameters for the power take-off functions are defined in the advanced signal acquisition and actuation module control unit (ASAM) (A7) and SAM with additional functions (XMC) (A22). Different regulation specifications can be made for each power take-off.

The parameters can be set individually. Initial prerequisites can be, for example:

 Parking brake applied

 transmission in neutral

 Rpm range (minimum and maximum)

 Torque limit

When the power take-off is switched on, the working speed can be set to between 550 rpm and 750 rpm. The setting occurs via the following component parts:

 The accelerator pedal

 The left multifunction steering wheel button group (S110) (vehicles with code J6A (classic cockpit))

 The right multifunction steering wheel button group (S111) (vehicles with code J6A (classic cockpit))

 The left finger navigation pad (FNPD) (A19a) (vehicles with code J6B (multimedia cockpit) or code J6C (multimedia cockpit, interactive))

The working speed can be set to a parameterized value via the working speed switch (S900).

Change working speed via the accelerator pedal

If the accelerator pedal sensor (B44) detects a change in the accelerator pedal position, the control unit of the drive control (CPC5) (A3a) changes the regulation specification for the working speed. It transmits this to the engine management control unit via the drive train CAN. The parameters specified by the advanced signal acquisition and actuation module control unit and SAM with additional functions are thus taken into account. This is likewise the current actual situation.

The engine management control unit increases the working speed by raising the injection quantity and keeps this constant.

Change working speed via the multifunction steering wheel

The working speed can be changed in steps of 20 via the multifunction steering wheel.

For vehicles with code J6A (classic cockpit), the left multifunction steering wheel button group and right multifunction steering wheel button group are connected via the button group LIN (LIN 7) to the instrument cluster (ICUC) control unit (A1).

For vehicles with code J6B (multimedia cockpit) or code J6C (multimedia cockpit, interactive), the finger navigation pad is connected via the user interface CAN (CAN 17) to the instrument cluster (IC) control unit (A151).

The commands are transmitted via the frame CAN (CAN 3) to the central gateway control unit (CGW) (A2) and to the control unit of the drive control. The control unit of the drive control compares the actual working speed with the target working speed, adjusts the regulation specification, and transmits it to the engine management control unit. If an upper/lower limit of the working speed is parameterized, this is taken into account.

When taking the current operating status of the engine into account, the engine management control unit calculates the injection quantity and the injection timing point. It actuates the fuel injectors and the quantity control valve correspondingly. Fuel is injected into the combustion chamber.

Change working speed via the working speed switch

The working speed switch takes on the special task of regulating the working speed.

The constant-rpm control can be activated via the working speed switch. The engine management control unit adjusts an engine speed parameterized especially for this purpose and keeps it constant, regardless of the load.